Footwear articles designed for wear on slippery surfaces such as wet ground, snow, or ice typically are provided with soles made of hard, heavy, waterproof material, e.g., rubber or plastic, and having treads, studs, spikes, or the like on the bottom thereof to improve traction on slippery surfaces. For example, U.S. Pat. No. 4,516,336 to Nissenbaum describes a footwear article plastic sole with a ribbed or toughened contact surface.
The uppers of known footwear articles designed for wear on slippery surfaces commonly are made of rubber, leather, or vinyl. As a result of the types of materials used to make them, these footwear articles tend to be heavy. Moreover, it has been found that many of these footwear articles do not provide adequate traction on slippery surfaces.
The use of hard rubber, leather, or vinyl in footwear also has disadvantages in insulating the foot of the wearer and keeping it warm. Since these materials are not breathable, heat, moisture, and salt from sweat generated by the foot of the wearer tend to be trapped in the footwear article. The sweat, composed of water, oils, minerals and salt, conduct body heat out of the footwear article, resulting in cold feet. This tends to make the entire body of the wearer feel colder.
It is also known to use soft, fibrous materials for footwear soles. For example, U.S. Pat. No. 4,217,704 to Whitaker describes an overshoe for wear when cleaning floors, having a sole made of non-woven synthetic fibers and an upper made of an elastomeric material such as rubber. U.S. Pat. No. 4,489,510 to Williams describes a shoe slipper for wear when cleaning floors, having a sole made of fibrous pads and an upper made of plastic. However, these footwear articles do not provide adequate breathability. Moreover, traction and comfort can be improved. Also, these footwear articles are not machine-washable nor are they used for snow and ice conditions.
U.S. Pat. No. 2,685,141 to Davenport describes a metallic, steel wool-type material for use as a sole attachment to provide traction on ice and snow. This material has weight, insulation, corrosion, and safety disadvantages.
It is also known to use leather as a sole material for footwear articles. For example, U.S. Pat. No. 2,718,715 describes a pac having a leather sole. Since leather is a relatively expensive material, products made of leather are relatively costly. Moreover, the use of leather as a footwear material is objectionable to those who disfavor products derived from animals. Also, leather is not thermally insulating, regardless if the leather is wet, dry or oiled.
A comfortable, lightweight footwear article providing improved traction is desirable. Lightness of weight allows for freedom and agility to quickly respond to hazards and changes in winter conditions during walking or climbing. Moreover, for wear in cold weather, a footwear article also having improved insulation is desirable. Furthermore, a footwear article that is machine-washable is desirable.